Araindrop of mass m0, starting from rest, falls under the influence of gravity. assume that as the raindrop travels through the clouds, it gains mass at a rate proportional to the momentum of the raindrop, dmr = kmrvr, where mr is the in- dt stantaneous mass of the raindrop, vr is the instantaneous velocity of the raindrop, 5 and k is a constant with unit [m−1]. you may neglect air resistance. (a) derive a differential equation for the raindrop’s accelerations dvr in terms of dt k, g, dt and the raindrop’s instantaneous velocity vr . express your answer using some or all of the following variables: k, g for the gravitational acceleration and vr, the raindrop’s instantaneous velocity.